K&N make replacement air filters that are soaked in special oil and you wash them and resoak them in oil every few thousand miles instead of throwing them away like paper filers. Some of the cone ones have a extra cloth cover that you can install cover it with for dusty environemnts such as off road. So carry some water for washing and the oil ro soak it in in your spares kit. A lot of newer vihicles are coming with passenger compartment air filters as well. My wife's car it was a $500 dealer option so we skipped it and I went to the service department and bought the $20 filter and put it in myself <img src="images/graemlins/smile.gif" alt="" />